Patent GB-731585-A (GB)
Title: Improvements in or relating to motor-driven pump units
IPC: F04D13/06
Filed: 1953-10-19
Abstract: 731,585. Screw pumps. ATELIERS DES CHARMILLES SOC. ANON., and GAILLOUD, L. Oct. 19, 1953 [Sept. 25, 1953], No. 28744/53. Class 110 (1). [Also in Groups XIX and XXXV] In a motor-driven pump. Fig. 1, in which the rotor 1 of the motor is immersed in liquid to be pumped and is separated from the stator 2 by a casing 5, the impeller shaft 3 is tubular and is supported on a stationary spindle 10, and the pump housing 7 has a removable cover 14, the spindle 10 being supported at one end by the cover 14 and at the other end by the casing 5, the latter end is provided with means enabling it to be secured relative to the casing 5 without radial play and without affecting the fluidtightness of the casing 5 and permitting the withdrawal of the spindle through the opening 13 closed by the cover 14. Bearings 11, 12 are interposed between the shaft 3 and spindle 10. One end of the spindle 10 is divided into four resilient sectors by means of two slots 26 at right angles to one another and fits with predetermined friction within a sleeve 25 secured to the casing 5. A pin 58 engages one of the slots 26 to prevent rotation of the spindle 10. The other end 19 of the spindle is gripped by a collet 17 having resilient sectors 18 which engage a conical part of a bore 16 in the cover 14. The collet is tightened by means of a nut 21. On removal of the nut, the collet can be pressed inwardly against the action of a spring 23 to couple it, through inter-engaging teeth 27, 28, to the shaft 3. The direction of rotation of the shaft 3 can thus be ascertained. The bearings 11, 12 are lubricated by liquid which leaks through the gap between a disc 29 and an adjacent housing part 30 to a chamber 31 and thence through the gap between the disc 29 and an annular projection 35. Finally, the lubricant passes through the gap between the spindle 10 and a ring 37. Centrifugal separation of impurities from the lubricant occurs at these three gaps and in the chamber 31. Chamfers 33, 38 assist in the separation. Impurities separated in chamber 31 pass through a passage 34 to the suction side of the pump. When the gap between the disc 29 and the part 30 tends to increase, the gap between the disc 29 and the annular projection 35 tends to decrease and vice versa, so that the flow of liquid through the gaps keeps the shaft 3 in axial equilibrium. On removal of the cover 14, the rotary parts can be withdrawn. On removal of screws 9, the stator 2 and its casing 8 can be removed without disturbing the remainder of the pump. In the modification shown in Fig. 8, the spindle 10 has a conical end 46 which engages a conical surface of a sleeve 48 carried by the casing 5. A spring 53 holds the end 46 against the conical surface and also tightens the collet 50. In further modifications, the conical end of the spindle 10 is followed by a threaded portion which engages a threaded part of the bore of the sleeve 48, and the end 19 of the spindle has a threaded portion which screws either into the cover 14 or into a nut outside the cover. In another modification, the spindle 10 is located relative to the casing 5 by a disc 54, Fig. 11, secured to the end of the spindle and engaging the inner periphery of the casing. The engaging surfaces of the disc and casing are slightly conical, to produce a tight fit. Alternatively, the disc is divided by slots at its periphery into resilient parts which press against the casing.